The present invention generally relates to medical devices and more specifically relates to a stent for maintaining patency of a body region.
There are many different kinds of endoprostheses, commonly called stents, which have the common characteristic of being presented into a patient's blood vessel or other body cavity or lumen in the shape of a cylinder, the wall of which forms a kind of lattice of deformable mesh in order to permit its diametrical expansion after being inserted into the body cavity in a contracted state.
A stent can maintain vascular patency by mechanically supporting vessels to prevent unintended closure. Stents can also be used to repair aneurysms, to support artificial vessels as liners of vessels or to repair dissections. Stents are suited to the treatment of any body lumen, including the vas deferens, ducts of the gallbladder, prostate gland, trachea, bronchus and liver. The body lumens typically range in diameter from small coronary vessels of about 3 mm or less to about 28 mm or more in the aortic vessel.
A typical stent is a cylindrically shaped wire formed device intended to act as a permanent prosthesis. A stent is deployed in a body lumen from a radially compressed configuration into a radially expanded configuration which allows it to expand to provide support to a body lumen.
The stent can be made to be radially self-expanding or expandable by the use of an expansion device such as a balloon catheter. A self expanding stent is made from a resilient springy material while an expandable stent is made from a material which is permanently deformable. An expandable stent can be implanted during an angioplasty procedure by using a catheter bearing a stent which has been secured to the catheter such as in U.S. Pat. No. 5,372,600 to Beyar et al. which is incorporated herein by reference in its entirety.
Commonly, stents are made of stainless steel or highly elastic metal alloy wires which are interwoven into a cylindrical mesh. The open weave wire structure typically results in loose wires at ends of the stent which can be traumatizing to the vessel walls in contact therewith. Sharp edges and loose wires oftentimes result in a fibrous change therein and the formation of an intraluminal scar which can be the nexus of another stenosis.
The present invention provides an improved apparatus for maintaining patency and/or causing patency or openness in a vessel or other body region of a living human or animal body.